Department of Neurology, Teikyo University School of Medicine, Tokyo, Japan.
Muscle Nerve. 2012 Aug;46(2):181-6. doi: 10.1002/mus.23292.
The frequent observation of high-amplitude and long-duration motor unit potentials (MUPs) in inclusion body myositis (IBM) is problematic, because it may lead to a misdiagnosis of amyotrophic lateral sclerosis (ALS).
To document the diagnostic utility of EMG from the flexor digitorum profundus (FDP) muscle for IBM.
Quantitative analyses of MUP parameters were performed in the FDP and biceps brachii (BB) muscles from 7 biopsy-confirmed IBM patients.
In the FDP muscle, all MUP parameters were significantly decreased in IBM patients, which indicated the predominance of low-amplitude and short-duration MUPs in this muscle. In the BB muscle, most parameters were increased, suggesting the frequent contamination of high-amplitude and long-duration MUPs.
Low-amplitude MUPs in the FDP muscle indicate the presence of an advanced myopathy in this muscle that was extremely weak for all subjects. Examining the FDP muscle would reduce the chance of misdiagnosing IBM as ALS.
在包涵体肌炎（IBM）中经常观察到高振幅和长时程运动单位电位（MUP）是有问题的，因为这可能导致肌萎缩侧索硬化症（ALS）的误诊。
记录来自指深屈肌（FDP）的肌电图在 IBM 中的诊断效用。
对 7 例活检证实的 IBM 患者的 FDP 和肱二头肌（BB）肌肉中的 MUP 参数进行定量分析。
在 FDP 肌肉中，IBM 患者的所有 MUP 参数均显著降低，这表明该肌肉中低振幅和短时程 MUP 占主导地位。在 BB 肌肉中，大多数参数增加，提示高振幅和长时程 MUP 的频繁污染。
FDP 肌肉中的低振幅 MUP 表明该肌肉存在进行性肌病，所有受试者的肌肉都极度无力。检查 FDP 肌肉可降低将 IBM 误诊为 ALS 的机会。
